1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for transmitting a paging message in a wireless communication system.
2. Related Art
A universal mobile telecommunications system (UMTS) is a third (3rd) generation asynchronous mobile communication system which is operated at wideband code division multiple access (WCDMA) based on European system such as global system for mobile communications (GSM) and general packet radio services (GPRS). Long-term evolution (LTE) and LTE-advanced (LTE-A) have been discussed as 4th generation mobile communication system by 3rd generation partnership project (3GPP) standardizing UMTS. 3GPP LTE and 3GPP LTE-A is technology for high speed packet communication. The 3GPP LTE requires cost reduction of a user and improvement of a service quality, extended and improved coverage and system capacity, flexible use of a frequency band, a simple structure, open interface and suitable power use of UE. To this end, various schemes have been suggested.
Further, it is expected that a request for data traffic is increased due to increase in image service and an ultra-high speed data service. Accordingly, as a solution scheme, there is a need for a scheme which may improve a whole efficiency and performance in all parts of the 4th mobile generation mobile communication system and additionally allocate a new frequency band. Accordingly, discussion for a 5th generation mobile communication system being a next generation mobile communication system starts.
Meanwhile, in the 4th generation mobile communication system and the 5th mobile communication system, various types of small cells such as a pico cell or a femto cell cooperate with a macro cell so that a radio access network (RAN) structure is changed. The 4th generation mobile communication system or the 5th mobile communication system is aimed at increasing quality of experience (QoE) by providing a high data transmission rate to a final user in a state that vertical multiple layer cells controlled by an existing macro cell coexist. The small cell is aimed at increasing spectrum efficiency by efficient deployment and operation. Ideal or non-ideal backhaul network may be supported between the macro cell and the small cell, and/or between small cells. The small cell may be provided in a sparse deployment environment and/or a dense deployment environment. In the next generation mobile communication system, construction of a small cell, to support increase in data traffic in a dense zone and indoor, may be significantly increased. Further, since researches for optimizing performance of small cells have been developed, the cells have a possibility to be developed to an operating system independently from the macro cell.
In recent years, discussion to improve indoor/outdoor scenarios using low power nodes has been performed. That is, research to provide a wireless communication service indoor/outdoor through a macro cell based on high-power node and a small cell based on a low-power node has been performed. Further, a work for obtaining advantages with respect to dual connectivity concept having a simultaneous connectivity in a macro cell layer and a small cell layer using the same or different carrier has been discussed. When considering such a trend, as a great number of small cells are deployed, it is expected that final users are physically located closer to a network.
Accordingly, in a radio access network of a 5th generation mobile communication system, it is expected that communication through user-centered virtual coverage other than existing physical cell based communication is achieved. In order to allow communication through the user-centered virtual coverage, a service provision unit such as user-centered virtual coverage distinguished from the existing cell based service provision unit should be implemented. This may cause a serious influence on a current wireless access network. For example, in a case of providing the user-centered virtual coverage, there may be a need for a new method of updating a tracking area and a new method of transmitting a paging message other than an existing method of updating a tracking area and an existing method of transmitting a paging message.